Neuronal responses in cat primary auditory cortex to electrical cochlear stimulation. I. Intensity dependence of firing rate and response latency

1994 ◽  
Vol 72 (5) ◽  
pp. 2334-2359 ◽  
Author(s):  
M. W. Raggio ◽  
C. E. Schreiner
Keyword(s):  
Electrical Stimulation ◽  
Stimulus Intensity ◽  
Response Latency ◽  
Transition Point ◽  
Complete Characterization ◽  
Stimulus Level ◽  
Electrode Spacing ◽  
Bipolar Electrode ◽  
Cochlear Prosthesis ◽  
Rate Level

1. Responses of neurons in primary auditory cortex (AI) of the barbiturate anesthetized adult cat were studied using cochlear stimulation with electrical and acoustic stimuli. Acoustic stimulation of the ear ipsilateral to the studied cortical hemisphere with brief biphasic clicks was compared with electrical stimulation of the contralateral cochlea with brief biphasic electrical pulses delivered via a feline cochlear prosthesis. The contralateral ear was deafened immediately before implantation of the cochlear prosthesis. The feline cochlear prosthesis consisted of four bipolar electrode pairs and was placed in the scala tympani. Two bipolar electrode conditions were used for stimulation: one near radial pair with electrode spacing of approximately 0.5 mm, and one longitudinal pair with electrode spacing of approximately 6 mm. 2. The firing rates obtained from single- and multiple-neuron recordings were measured as a function of stimulus intensity for single electrical and acoustic pulses. Resulting rate/level functions were characterized by a fast growing low-level segment and a more slowly growing, saturating, or decreasing high-level segment. The slopes of these two segments as well as the stimulus level and firing rate at the juncture of these two segments (the transition point) provide a complete characterization of the response magnitude behavior as a function of stimulus intensity. 3. The main characteristics of rate/level functions obtained with electrical and acoustic cochlear stimulation were quite similar. However, for any given neuron, differences in the primary growth behavior, such as monotonic or nonmonotonic growth, could be observed between the different stimulation modes. 4. Response latencies from single- and multiple-neuron recordings were obtained as a function of stimulus intensity for electrical and acoustic pulses. Resulting latency/level functions were characterized by a rapidly decreasing low-level segment and a more slowly decreasing high-level segment. The slopes of these two segments as well as the stimulus level and response latency at the juncture of these two segments (the transition point) provide a complete characterization of the response latency behavior as a function of stimulus intensity. Transition point levels for the rate/level function and the latency/level were nearly identical. 5. The characteristic latency behavior for each neuronal response was found to be very similar for acoustic and electrical stimulation. Correlation analysis revealed a close relationship between latency parameters of the two electrical stimulation conditions, a weaker relationship between the longitudinal electrical and the acoustic conditions, and the weakest relationship between the radial electrical and acoustic conditions. 6. Correlation analysis for rate and latency parameters revealed several relationships between these response aspects.(ABSTRACT TRUNCATED AT 400 WORDS)

Neuronal responses in cat primary auditory cortex to electrical cochlear stimulation. II. Repetition rate coding

1996 ◽  
Vol 75 (3) ◽  
pp. 1283-1300 ◽  
Author(s):  
C. E. Schreiner ◽  
M. W. Raggio
Keyword(s):  
Electrical Stimulation ◽  
Firing Rate ◽  
Repetition Rate ◽  
Cortical Neurons ◽  
Primary Auditory Cortex ◽  
Acoustic Stimulation ◽  
Electrode Spacing ◽  
Bipolar Electrode ◽  
Cochlear Prosthesis ◽  
Cutoff Frequencies

1. Responses of neurons in primary auditory cortex (AI) of the barbiturate-anesthetized adult cat were studied using cochlear stimulation with electrical and acoustic stimuli. Neuronal responses to acoustic stimulation with brief biphasic clicks of the ear ipsilateral to the studied cortical hemisphere were compared with those evoked by electrical stimulation of the contralateral cochlea with brief biphasic electrical pulses delivered via a feline cochlear prosthesis. The contralateral ear was deafened immediately before implantation of the cochlear prosthesis. The feline cochlear prosthesis consisted of four bipolar electrode pairs and was placed in the scala tympani. Two bipolar electrode conditions were used for stimulation: one near radial pair with electrode spacing of 0.25-0.5 mm, and one longitudinal pair with electrode spacing of approximately 6 mm. 2. The firing rates obtained from single- and multiple-neuron recordings were measured as a function of stimulus repetition rate of electrical and acoustic pulses. From period histograms over a recording interval of 1,000 ms, the driven firing rate to repetition rates from 2 to 38 Hz was obtained and repetition rate transfer functions (RRTFs) were constructed. The RRTFs were characterized as low-pass or band-pass filters and several descriptors were obtained, such as the repetition rate producing the highest driven activity, high and low cutoff frequencies 6 dB below maximum firing rate, and maximum firing rate. 3. For a given neuron, the main characteristics of cortical RRTFs obtained with electrical and acoustic cochlear stimulation were quite similar. However, some small but statistically significant differences in the best repetition rate, cutoff frequencies, and maximum firing rate could be observed between the different stimulation modes. The proportion of band-pass RRTFs was larger for electrical stimulation (57%) than for acoustic stimulation (41%). The high cutoff frequencies for electrical stimulation were slightly but consistently higher than for acoustic RRTFs of the same neuron and the maximum firing rate for electrical stimulation was significantly higher than that evoked by ipsilateral acoustic stimulation. 4. The entrainment of cortical neurons to electrical and acoustic pulses was determined and entrainment profiles were constructed. For a given neuron, electrical entrainment profiles showed higher cutoff frequencies than with acoustic stimulation when judged with a fixed entrainment criterion of 0.25 spikes per event. The maximum entrainment seen for electrical stimulation was approximately 20% higher than seen for the same neuron with acoustic stimulation. 5. Correlation analysis of repetition coding and latency parameters revealed several relationships between these response aspects. Most prominent among them was a significant correlation between measures of the response latency and estimates of the ability to follow temporal repetitions for acoustic as well as electrical conditions. 6. Parametric and comparative evaluations of cortical responses to acoustic and electrical cochlear stimulation support the conclusion that the temporal resolution seen in cortical neurons is largely a consequence of central processing mechanisms based on cell and circuit properties and to a lesser degree a consequence of particular spatial and temporal peripheral excitation patterns. The slightly higher temporal resolution found for the electrical stimulation modes suggests that the temporally highly coherent electrical stimulation appears to engage, in a more effective manner, the excitatory/inhibitory mechanisms contributing to the response in AI than acoustic click stimulation with less temporal coherence. (ABSTRACT TRUNCATED)

Temporal-Gap Detection by Cochlear Prosthesis Users

1989 ◽  
Vol 32 (4) ◽  
pp. 849-856 ◽  
Author(s):  
John P. Preece ◽  
Richard S. Tyler
Keyword(s):  
Magnitude Estimation ◽  
Stimulus Level ◽  
Electrode Placement ◽  
Frequency Effect ◽  
Gap Detection ◽  
Cochlear Prosthesis ◽  
Sensation Level

Minimum-detectable gaps for sinusoidal stimuli were measured for three users of a multi electrode cochlear prosthesis as functions of stimulus level, frequency, and electrode place within the cochlea. Stimulus level was scaled by sensation level and by growth-of-loudness functions generated for each condition by direct magnitude estimation. Minimum-detectable gaps decreased with increase in either sensation level or loudness, up to a plateau. When compared at equal sensation levels, the minimum-detectable gaps decreased with frequency increases. The frequency effect on minimum-detectable gaps is reduced if the data are considered at equal loudness. Comparison across place of stimulation within the cochlea showed minimum-detectable gaps to be shorter for more basal electrode placement at low stimulus levels. No differences in minimum-detectable gap as a function of place were found at higher stimulus levels.

Electrical Stimulation of the Guinea Pig Cochlea

1987 ◽  
Vol 96 (4) ◽  
pp. 349-361 ◽  
Author(s):  
Mark J. Maslan ◽  
Josef M. Miller
Keyword(s):  
Electrical Stimulation ◽  
Low Frequency ◽  
Damage Threshold ◽  
Auditory Brainstem ◽  
Cochlear Prosthesis ◽  
Before And After ◽  
Auditory Brainstem Evoked Responses ◽  
Straight Lines ◽  
Histopathologic Findings ◽  
Stimulation Of

As a result of practical considerations, histopathologic findings of the temporal bone in humans with cochlear prosthesis implants have been limited. This project attempts to better define safe parameters of electrical stimulation of the inner ear and compare the safe limits of intracochlear vs. extracochlear stimulation sites. Guinea pigs were implanted with single electrodes either on the promontory or in the scala tympani and were stimulated relative to a remote indifferent for 12 hours distributed over a 4-week period. Electrical auditory brainstem evoked responses (EABRs) were tested before and after each of four 3-hour stimulation sessions. Six weeks after implantation, the animals were killed, and their cochleas were examined under the scanning electron microscope. Intracochlear electrodes exhibited thresholds for damage well below one half of that found for most extracochlear stimulation sites. The function-relating damage threshold (in amperes) to frequency of intracochlear stimulation is represented by two straight lines, with an intercept of 1 kHz. The low-frequency limb exhibited a slope of 3 to 4 dB/octave, whereas the high-frequency limb exhibited a slope of 9 to 10 dB/octave. Extracochlear results were too variable to permit speculation. Changes in EABRs were only variably related to histopathologic findings.

Apparent Duration as a Function of Intensity of Vibrotactile Stimulation

1969 ◽  
Vol 28 (1) ◽  
pp. 151-156 ◽  
Author(s):  
Goesta Ekman ◽  
Marianne Frankenhaeuser ◽  
Birgitta Berglund ◽  
Michael Waszak
Keyword(s):  
Electrical Stimulation ◽  
Stimulus Intensity ◽  
Index Finger ◽  
Left Index Finger ◽  
Estimation Technique ◽  
Logarithmic Function ◽  
Vibrotactile Stimulation ◽  
Apparent Duration ◽  
Fixed Standard ◽  
Stimulation Of

8 Ss were exposed to vibrotactile stimulation of 250 Hz, applied to the tip of the left index finger. Seven stimulus intensities, ranging from 26 to 48 db, were each combined with three stimulus durations, 50, 250, and 1200 msec. A magnitude-estimation technique with fixed standard was employed to obtain scale values of the apparent duration of each stimulus. The results indicate that apparent duration can be described as a logarithmic function of stimulus intensity. This conclusion is in line with our previous findings concerning apparent duration of electrical stimulation.

ELECTRICAL STIMULATION OF THE HYPOTHALAMUS AND LUTEINIZING HORMONE SECRETION IN JAPANESE QUAIL

1975 ◽  
Vol 67 (3) ◽  
pp. 431-438 ◽  
Author(s):  
D. T. DAVIES ◽  
B. K. FOLLETT
Keyword(s):  
Electrical Stimulation ◽  
Hormone Secretion ◽  
Relative Increase ◽  
Significant Rise ◽  
Bipolar Electrode ◽  
Luteinizing Hormone Secretion ◽  
Coturnix Coturnix ◽  
Electrolytic Lesions ◽  
Lh Secretion ◽  
Stimulation Of

SUMMARY Experiments were undertaken to localize those hypothalamic areas in the male quail (Coturnix coturnix japonica) where electrical stimulation would increase LH secretion. The posterior basal hypothalamus was stimulated with rectangular pulses (height 500 μA) through a bipolar electrode for 6 min, blood samples being taken for LH assay 20 min before, and 2, 10, 20 and 30 min after stimulation. The highest plasma concentration was observed in the 2 min sample. Over the next 30 min the LH level decreased to the resting concentration. The relative increase in LH level was greatest in sexually immature quail and least in photostimulated castrated birds, although the highest absolute levels were seen in the castrated quail. There were no statistical differences between the magnitude of the LH increases in sexually immature, mature and castrated quail. Various hypothalamic regions were then stimulated with a smaller current (200 μA) applied for only 2 min. A highly significant rise in LH followed stimulation of either the tuberal hypothalamus (postero-dorsal part of the infundibular nuclear complex, PD-INC), or the preoptic region (POR) while stimulation 0·5–1·5 mm away from these regions did not change LH secretion. Stimulation of the anterior basal hypothalamus, or of the suprachiasmatic area, caused a significant rise in LH concentration although this was less than that seen after stimulation of the POR. Stimulation in the POR or the PD-INC was ineffective if the tuberal hypothalamus had been deafferentated surgically some days previously. The data complement the studies in which destruction of the PD-INC or the POR by electrolytic lesions has been shown to block photoperiodically induced testicular growth and LH secretion.

Acute Morphological Changes in Guinea Pig Cochlea following Electrical Stimulation

1982 ◽  
Vol 91 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Larry G. Duckert ◽  
Josef M. Miller
Keyword(s):  
Electrical Stimulation ◽  
Guinea Pig ◽  
Basilar Membrane ◽  
Morphological Changes ◽  
Supporting Cell ◽  
Cochlear Prosthesis ◽  
Cell Degeneration ◽  
Constant Intensity ◽  
Temporal Bones

A major area of concern in the development of the cochlear prosthesis involves the effects of the implant on inner ear anatomy and function. This study examined one aspect of host-implant interaction — the effects of cochlear implantation with and without electrical stimulation on cochlear morphology in the guinea pig. To accomplish this, a series of normal guinea pigs were acutely implanted bilaterally with a scala tympani multiple electrode prosthesis. One ear was stimulated with continuous 1 kHz sinusoidal current of constant intensity for a period of three hours. The contralateral control ear was not stimulated. Current intensities tested ranged from 0.1 mA to 1 mA rms. After stimulation the animals were sacrificed, perfused with fixative and the temporal bones were microdissected for examination using the scanning electron microscope. Morphological changes observed in the stimulated ear ranged from hair cell and supporting cell degeneration to complete destruction of the basilar membrane and organ of Corti overlying the electrode. These changes occurred at current intensities ranging from 0.4 mA to 1 mA and were conspicuously absent in the implanted but unstimulated control ears. The current intensities employed in this experiment were within operating ranges presently used in long-term behavioral studies in other animal models. To what degree the morphological changes observed in this study may effect the function of the prosthesis or host responses on a long-term basis cannot be determined from this experiment. However, our observations do demonstrate that electrical stimulation of the cochlea is not benign and point out the need for further evaluation to help define safe standards for use of the prosthesis.

Short-Latency Acceleration of Human Heart Rate as a Function of Stimulus Intensity

1977 ◽  
Vol 45 (2) ◽  
pp. 579-583 ◽  
Author(s):  
J. G. O'Gorman ◽  
R. D. Jamieson
Keyword(s):  
Heart Rate ◽  
White Noise ◽  
Stimulus Intensity ◽  
Human Heart ◽  
Short Latency ◽  
Rate Level ◽  
Initial Values ◽  
Heart Rate Level ◽  
The Mean ◽  
Female Subjects

The study examined the effectiveness of three intensities of white noise in evoking short-latency acceleration of human heart rate. 3 groups of 10 female subjects were presented with 1-sec. bursts of white noise with virtually instantaneous rise times at intensities of 100 db (re 20 μN/m2), 90 db, or 80 db SPL as measured at the headset. 5 bursts were presented at intervals of 45 sec. while the EKG was recorded. An increase in heart rate during poststimulus beats 3 and 4 compared with the mean rate of the three beats prestimulus was reliably evoked on the first two trials in the 100-db and 90-db groups but not in the 80-db group. Apart from a recovery of acceleration on Trial 5 for the 100-db group, the 100-db and 90-db groups did not differ in amplitude or rate of habituation of the response. Poststimulus heart-rate level was not significantly related to prestimulus level as expected in terms of the law of initial values. The results were interpreted as consistent with F. K. Graham's interpretation of short-latency cardiac acceleration as a component of startle.

scholarly journals Binocular 3D otolith-ocular reflexes: responses of chinchillas to prosthetic electrical stimulation targeting the utricle and saccule

2020 ◽  
Vol 123 (1) ◽  
pp. 259-276 ◽  
Author(s):  
Kristin N. Hageman ◽  
Margaret R. Chow ◽  
Dale Roberts ◽  
Peter J. Boutros ◽  
Angela Tooker ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Hair Cells ◽  
Temporal Dynamics ◽  
Semicircular Canals ◽  
Bipolar Electrode ◽  
Electrode Arrays ◽  
Reflex Responses ◽  
Ocular Reflex ◽  
Postural Responses ◽  
Stimulation Of

From animal experiments by Cohen and Suzuki et al. in the 1960s to the first-in-human clinical trials now in progress, prosthetic electrical stimulation targeting semicircular canal branches of the vestibular nerve has proven effective at driving directionally appropriate vestibulo-ocular reflex eye movements, postural responses, and perception. That work was considerably facilitated by the fact that all hair cells and primary afferent neurons in each canal have the same directional sensitivity to head rotation, the three canals’ ampullary nerves are geometrically distinct from one another, and electrically evoked three-dimensional (3D) canal-ocular reflex responses approximate a simple vector sum of linearly independent components representing relative excitation of each of the three canals. In contrast, selective prosthetic stimulation of the utricle and saccule has been difficult to achieve, because hair cells and afferents with many different directional sensitivities are densely packed in those endorgans and the relationship between 3D otolith-ocular reflex responses and the natural and/or prosthetic stimuli that elicit them is more complex. As a result, controversy exists regarding whether selective, controllable stimulation of electrically evoked otolith-ocular reflexes (eeOOR) is possible. Using micromachined, planar arrays of electrodes implanted in the labyrinth, we quantified 3D, binocular eeOOR responses to prosthetic electrical stimulation targeting the utricle, saccule, and semicircular canals of alert chinchillas. Stimuli delivered via near-bipolar electrode pairs near the maculae elicited sustained ocular countertilt responses that grew reliably with pulse rate and pulse amplitude, varied in direction according to which stimulating electrode was employed, and exhibited temporal dynamics consistent with responses expected for isolated macular stimulation. NEW & NOTEWORTHY As the second in a pair of papers on Binocular 3D Otolith-Ocular Reflexes, this paper describes new planar electrode arrays and vestibular prosthesis architecture designed to target the three semicircular canals and the utricle and saccule. With this technological advancement, electrically evoked otolith-ocular reflexes due to stimulation via utricle- and saccule-targeted electrodes were recorded in chinchillas. Results demonstrate advances toward achieving selective stimulation of the utricle and saccule.

Sign in / Sign up

Export Citation Format

Share Document